Răspuns:
Explicație pas cu pas:
a/b = 1,25
1,25 = 125/100 = (125:25)/(100:25) = 5/4
a/b = 5/4
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a/b : 7/8 = (5/4) × 8/7 = (8/4) × 5/7 = (2×5)/7 = 10/7
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a/b : ( - 5) = (5/4) × ( - 1/5) = -(5/5) × (1/4 ) = - 1/4
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( - 5 ×a) : b/2 = - 5 × a × (2/b) = - 10 × (a/b) = - 10 × 5/4 = - 50/4 =
= - (50:2)/(4:2) = - 25/2 = - 12,5
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a/5 : ( - b/4) = a/5 × ( - 4/b) = (a/b) × ( -4/5) = (5/4) × (-4/5) = - 1
5/4 × ( - 4/5) = (5/5) × ( - 4/4) = 1 × ( - 1) = - 1
